ios - 调整 UITextView 高度以适应 UITableViewCell 中的文本

Question

我目前正在构建一个在表格中显示用户帖子的社交网络应用程序。每篇文章将显示在表格的一个单元格中。因为我不知道用户会为一篇文章输入多少内容，所以我需要根据用户输入的文本量来设置 TextView 大小。问题是我当前的实现不工作并且行为异常。

这是我的表格代码:

override func tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat {

    let cell : UITableViewCell? = tableView.dequeueReusableCellWithIdentifier("HomeCell") as? UITableViewCell
    let post : Post = tblData[indexPath.row]

    //Get all custom cell components
    let userLbl = cell?.viewWithTag(101) as UILabel
    let timeLbl = cell?.viewWithTag(102) as UILabel
    let postLbl = cell?.viewWithTag(103) as UITextView
    let profilePic = cell?.viewWithTag(100) as UIImageView
    let postPic = cell?.viewWithTag(104) as UIImageView

    //Post lbl properties
    let textHeight = textViewDidChange(postLbl)
    postLbl.frame.size.height = CGFloat(textHeight)
    //postLbl.selectable = false

    //Individual height variables
    let postInfoHeight = 66 as CGFloat
    var postHeight = 8 + CGFloat(textHeight)
    var imgHeight = 8 + postPic.frame.height as CGFloat

    if post.postInformation == "" {
        postLbl.removeFromSuperview()
        postHeight = 0
    }

    if post.img == nil {
        postPic.removeFromSuperview()
        imgHeight = 0
    }

    //Change the autolayout constraints so it works properly
    return postInfoHeight + postHeight + imgHeight
}

下面是计算 TextView 高度的代码:

func textViewDidChange(textView : UITextView) -> Float {

    let content : NSString = textView.text
    let oneLineSize = content.sizeWithAttributes(["NSFontSizeAttribute": UIFont.systemFontOfSize(14.0)])

    let contentSize = CGSizeMake(textView.frame.width, oneLineSize.height * round(oneLineSize.width/textView.frame.width))

    return Float(contentSize.height)
}

我不明白为什么这没有给我正确的结果。如果有人能发现错误或建议如何解决此问题，我将不胜感激。提前致谢!

Answer 1

感谢@jrisberg 提供指向其他问题的链接。我决定放弃使用 TextView ，现在改用 UILabel。另一个问题中的代码非常古老并且使用了很多不推荐使用的方法，所以我将在此处发布一些适用于 iOS 8 的更新代码。我删除了 textViewDidChange(textView : UITextView) 方法并将我的 tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) 方法更改为:

override func tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat {

    let cell : UITableViewCell? = tableView.dequeueReusableCellWithIdentifier("HomeCell") as? UITableViewCell
    let post : Post = tblData[indexPath.row]

    //Get custom cell components
    let postLbl = cell?.viewWithTag(103) as UILabel
    let postPic = cell?.viewWithTag(104) as UIImageView

    //Post lbl properties
    let PADDING : Float = 8
    let pString = post.postInformation as NSString?

    let textRect = pString?.boundingRectWithSize(CGSizeMake(CGFloat(self.tableView.frame.size.width - CGFloat(PADDING * 3.0)), CGFloat(1000)), options: NSStringDrawingOptions.UsesLineFragmentOrigin, attributes: [NSFontAttributeName : UIFont.systemFontOfSize(14.0)], context: nil)

    //Individual height variables
    let postInfoHeight = 66 as CGFloat
    var postHeight = textRect?.size.height
    postHeight? += CGFloat(PADDING * 3)
    var imgHeight = 8 + postPic.frame.height as CGFloat

    if post.img == nil {
        postPic.removeFromSuperview()
        imgHeight = 0
    }

    //Change the autolayout constraints so it works properly
    return postInfoHeight + postHeight! + imgHeight
}